"The intermixing of races" is detectable patrilineally via Y-DNA and matrilineally via mtDNA.
The reason I put the phrase above in quotes is via DNA testing there's no such thing as a "race" anymore as you think of it. Hence, the phrase is meaningless. I used it here only to frame the context of the discussion.
The "races" are haplogroups and gene markers. No more than that and no less than that.
Hence, when you say "intermixing of races" what do you mean by it? Some amorphous anthropological or cultural theoretical construct based on what scientists in the 1800s meant by race?
Or are you talking families (haplogroups) of DNA?
What exactly do you even mean by that statement?
I thank you as well and welcome any further comments you have and fully understand if you do not wish to explore it further here. Cheers!